OCR AS Biology Unit 2 (F212) presentation on enzymes

I did a powerpoint presentation for my biology class and i thought i would put it on here to help others out. Along with it i did a word document with the presentation in note form and gaps that can be filled in while going throught it. I will put it on here as well so if you fancy a bit of biology revision it may help you out. 

The exam board is OCR and this is the unit 2 topic of enzymes (F212) 

Thank you and good luck with your revision.

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  • Created by: Faye
  • Created on: 15-04-13 20:07

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Slide 1

Slide 2

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WHAT IS AN ENZYME?
Globular proteins
Acting as catalysts
They are specific
Enzymes have an active site which fits a
specific substrate
Their activities are affected by
Temperature and PH…read more

Slide 3

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HOW DO ENZYMES WORK
All enzymes reduce the activation energy
required for the reaction.
2 Hypotheses:
Lock and key ­ an enzyme has a specifically
shaped active site which is complementary to
the shape of the substrate.
Induced fit ­ as the substrate and the enzyme
molecules collide the enzyme changes shape
slightly so the active site fits more closely
around the active site.…read more

Slide 4

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WHAT EFFECTS THE ACTIVITIES OF
AN ENZYME?
PH
A PH that is too high for an enzyme causes
the H+ ions to attack the tertiary structure of
the enzyme which causes them to denature.
A PH too low for an enzyme does not give the
enzyme enough H+ ions to maintain the
tertiary structure
When a PH is at its optimum for an enzyme
the reaction occurs at its maximum rate.…read more

Slide 5

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The optimum PH changes form enzyme to
enzyme.
Eg/ Pepsin and Trypsin
Pepsin Trypsin
Rate
of
reaction
PH…read more

Slide 6

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The different optimum values are due to the
places where the enzymes are found.
Pepsin is found in the stomach so therefore
needs a low PH optimum so it doesn't
denature in the stomach acid.
Trypsin is found in the small intestine which
has alkaline conditions and therefore the
optimum PH needs to be high.…read more

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